Fig. 6

Molecular model for C3b density. a The crystallographic structure of C3b [PDB:2I07]. b Model for C3b density on a 150 × 150 nm area representing a portion of the bead surface. For each C3b density, the number of molecules per 150 × 150 nm surface area was calculated, and intermolecular distance was calculated assuming a uniform distribution of molecules. C3b molecules were then placed such that the center-to-center distance was equal to the calculated intermolecular distance. C3b is oriented such that the long axis is perpendicular to the surface and the thioester (and in turn the biotin linker) was in contact with the surface